Loading and unloading gear for hoisting plants



Se t. .16 1924.

P F. M. cAs'rLEMAN LOADING AND UNLOADING GEAR FOR HOISTING PLANTS Filed March 1'7 1920 l ,M1 ATTORNEY Sept. 16 1924.

1,508,921 n F. M. cAsTL-EMAN LOADING AND UNLOADING GEAR FOR HOISTING PLANTS Filed March' 17 4 sheets-sheer, '2

m o .H

C) INVENTOR.;

aYQ-'Z" H'll ATTORNEY Sept. 16 1924.

F. M. cAsTLEMAN LOADING AND UNLOADING GEAR FOR HOISTINQPLAN'IS Filed March 17g, 19.20 4 sheets-sheet s 6L-xm. Me ATTORNEY I Sept. 16 1924.

F. M. CASTLEMAN LOADING AND UNVLOADING GEAR FOR HOISTNG PLANTS 4 Sn'eemsheet 4 Flle@ March 17, 1920 31: .Jima i INVENTOR;

Y v B mam@ 164112, 'ATTORNEY Patented Sept. 16, 1924..

FRANK NI. oAs'rLniJIAN, or normanna; ENGLAND, assIeNon,` :BY MnsNE As'sIe-N- MENTS, rro THE UNION SWITCH a sIeNaL COMPANY, or sWIssvAnE, rnNNsYLF VANIA, A. CORPORATION or rnNNsYLvnNIA.

LOADING AND 'UNLOADNG GEAR FOR HOISTING- PLANTS.

Application inea March 17, 1920. serial No. 366,714.

To all whom t may concern.' y

Be it known that I, FRANK MASTERS CAS- TLEMAN, a subject of the King of 'Great Britain, residingy at Rotherham, in the county of Yorkshire, England, have invented a certain new and useful improvement in Loading andUnloading Gears for Hoisting Plants, of which the following is a specification.

This invention relates to loading and unloading gear for hoisting plant and the like and particularly although not exclusively to decking plant as employed in collieries and other mines of the kind comprising a hoisting cage having one or more decks and arrangements for vloading and unloading empty and full tubs or trucks on to and from the cage respectively.

The invention has for its object to provide improved arrangements and apparatus for effecting the transfer of the tubs or trucks to and from the hoisting cage which shall be eiiicient and to a greater or lessy extent, as desired, automatic in operation while ensuring a higher degree of safety in working than has hitherto been possible.

The invention contemplates the provision of one or more power-operated rams for driving empty tubs or trucks on to the hoisting cage when the latter is in its proper position, thereby displacing'the full tubs from the cage on to a tub hoist, track or other arrangement adapted to receive thein.l

According to the principal feature of the invention the control mechanism for the power-operated rams is arranged to be electrically interlocked with mechanism for securing the hoisting cage in position during the loading and unloading operation, thereby enabling thelatter to be carried out with absolute security and at the same time obviating unnecessary delay. v

Further features of the invention relate to arrangements for causing an automatic return motion of the ram mechanism after placing the empty tubs in position upon the hoisting cage, and a general system of electric interlocking and indication circuits whereby absolutesecurity against improper operation of any part of the gear may be obtained. l The invention is illustrated diagrammatically in the accompanying drawings as aption and showing the general'arrangeme'nt of the pit head mechanism with the hoisting cage in position lfor unloading.-

, Figure 2 is a clrcuitdiagram showing the electrical connections and `interlocking -circults employed ure 1.

Figure 3 is a simplified diagram ofthese `circuits which will be hereinafter referred 'to in the description. y

Fig. -i is a sectional view showing the kep motor 8 and operating magnets 9. and 10 illustrated in outline in Figspl andQ.

Fig. 5 is a plan view` showing one form of automatic axle counter and unlocking motor mechanism associated therewith. Fig. 6 is a side elevation, andk Fig. 7 an end elevation, of the apparatus shownin Fig. 5, while Fig. 8 is a detail of one of the parts of said apparatus.

Fig. 9 is a view showing an axle counter forming part of the ,plant illustrated in Figs. 1 and 2. t Fig. 10 is a view showing amodified form of. axle counter also constituting part of the plant illustrated in Figs. 1 and 2;

Fig. 11 is a view showing in side elevation the head of a ram 51 .formingv part of the plant illustrated in Figs. land 2. Fig. 12 is an end view of thewram 51, and Fig. 13 is a sectional view of the motor mechanism of this ram.

Similar reference characters refer to Asimilar parts in each ofthe several views.

Referring now first to Figure 1,-the hoist- Ing cage 1s indicated diagrammatically at 1 as of the center double deck. type, a full tub hoist indicated at 2 being shown as lov cated on one side ofthe cage 1 andan empty tub hoist?) on the other side. lThe upper and lower decks 4; and 5 respectivelyv of the hoisting cage 1 are each shown as containing three tubs or trucks 6 which have been raised to the pit head by means of the cage 1 which is operated by the usual hoistingmechanism. In order to lock or secure the hoisting cage in the positionk shown a number of keps7 indicated at 7 are provided which are arranged to be placed in position under the cage 1 and withdrawn there-` in the installation of Fig- On the entrance side oi the cage j... niely the right hand side as shoivn in e l, each ot the decks t? 5 is providec a automatic back stop l2, 13 comprising? pivoted arin over which the aviles oi" the tnhs can freely pass hat which prevents their inoveinent in the reverse direction. The

back stops 127 13 are each provided vvipi indication Contact device A, l5 i'f-snectively each comprising apair of siv tclies adapted to loe automaticall;7 closel l l" hack stop is in its norinal or operaiprevent movement of the tuhs direction.

rllhe decks Il, 5 of the cage oy that is to say the lett hand are each provided with an counter or stop i6, l? resoe ing tulos in thev cage. Tl. these aXle counters is siicli ite nuinber or ailes and have passed the counter7 the automatically and prevents to sage of tuhs over the counter i.; is again unlocked by a inotoi indicated diagraininaticallj/ at l i forni of axle counter and unlocx mechanism is illustrated in Figs. 5a G, /l' C.nd 8 and is described hereinart ,1. The con i unlocking devices 18, provided indication contacts shown dial at 20, 2l respectivelyv eacli number of switches adapted disconnect electric indication he hereinafter described.

lt should loe observed that the in ni otori to coinplete or circuits as will ters or stops 1G, l? ae inonnted i hoisting cage l tsel Whereas t1 l, 1 r unlec i inechanisnis i555 19 to C, counters are inounted upon me portion of the pi lead n'ieelianif the electric connu ors nets of the niotor ,noch

Il JA fr ier the coii liao are not attached to tY tii Aie the pit head on hoisting cage 1 a gate 522 is ed to be autoniaticaiij/v rais-Yy Q;

the latter rises to th Q2 is provided With dcvce 23 adapted to the gate is fully lifted. oi a vice is operated lov a stein 112 attached to the gate. Tl'iehoisting cage itseilf is als provided with an indication Contact devic 24 adapted to he closed only when the cage is at the proper level for unloading, this Contact being operated by a stein lli-l attached to tL ie eiiipty tub hoist indicated at 3 is a e u deck type and coinprises tiro and c to the deel-s Th.. il.

, e ectivel!v o' the hoisting` cage l The tulo lioist provided n its enit side With aille counters or stops 2T, 2 aid e ec tricallyv controlled iinloeliii inotors there- "^r indicated at 53th 30 together vith indica-- iva .'l these e.

vV evices lacing tion contacts 3l. 52 il o to ao piro-A i oi to ove @o respectively iso provided with adapted Lo he t is in tl V.ls't o i intoane fri-oni f iauf'ing by fi ieans or new to th] Mell tub hoist indi` cated at f2 this is lli, siinilar iii ineclanical construction ani peinent to the en hoist 3 he'no provided with trio l f respeetivel"i each ca ating); three i or triicl 'lie entrai ce side or the v:de counter eoiitacts 43 .lar to those HV,

olli,

acl. stops l2. and provided .l

decl; oit

incre i ivliicn the hoist sliov n in the upper deck 38 of the hoist is on the level of this latter indication contact. Contact 45 is operated by a stem 110, and contact 46 by a stem 111, both of which are attached to the hoist 2 in suitable positions.

On the side of the full tub hoist 2 remote from the hoisting cage 1 a track indicated at 47 is provided for the reception of the tubs leaving the tub hoist 2 an automatic axle counter indicated at 48 being provided as shown. The axle counter 48 is similar in construction to those indicated at 40, 41 except that it is arranged to close one pair of switch contacts when six axles have passed over the counter and to close another pair of contacts when a further six axles have passed. One form of counter suitable for this purpose 'is illustrated in Fig. 10 and described hereinafter. The hoist 2 is arranged to be lowered from the position shown in Figure 1 to a position in which the upper deck 38 is on the same level as the track 47 for the purpose of discharging the tubs carried by the deck 38 and this movement of the hoist is arranged to be effected by mechanism illustrated diagram'- matically at 49 comprising a pneumatic or other fluid pressure device controlled by an electro-magnetically operated valve indicated at 50.

On the right hand side of the empty tub hoist 3 two power-actuated rams 51 and 52 are providedone for each deck of the hoisting cage and hoists, the operation of the rams 51, 52 being controlled by electro-magnetically actuated valves 53, 54 respectively. The structures of these rams are illustrated in Figs. 11, 12 rand 13, and are described hereinafter. provided whichl are adapted to be closed only when the rams are in their inoperative or fully retracted position as shown in Figure 1.

Located intermediate the hoisting cage 1 and the empty tub hoist 3 are a pair of indication contacts 57, 58 adapted to be operated by the rams 51, 52 when the latter reach their forward position as will be hereinafter described. A second pair of indication contacts 59, 60 are also provided` adapted to be closed only when the ram heads are clear of the hoisting cage 1 during the return movement of the rams 51, 52.

Referring now to Fig. 4, the kep motor 8 comprises a cylinder 115 containing a piston 116, to which is attached a rod 117 passing out through a` packing gland 118, and terminating in a yoke 119 which is attached to the kep operating links and cranks 133, shown in Fig. 1. Fluid pressure is admitted to one end of the cylinder 115 through a port 123 and to the other end of this cylinder through a port 122, the connection of these ports with the source of fluid pressure and with atmosphere being controlled by a Indication contacts 55, 56 are slide valve 120 operating in a chamber 121 which is constantly connected with a source of fluid pressure not shown in the drawing. When the valve 120 occupies the position in which it is shown, port 123 is connected with atmosphere through an exhaust port,`

124, whereas port 122 is connected with fluid pressure so that piston 116 is at the lefthand end of the stroke. In this position the keps 7 are in locking positions, as shown in Fig. 1. When the slide valve 120 is reversed, port 122 will lbe connected with at'- mosphere and port 123 will be supplied with uid pressure, so that piston 116 will be moved to the right and so will withdraw the keps from their lockingpositions.

Theslide valve 120 is controlled by a piston 126 operating in a cylinder 125 and also by a piston 126aM operating in a cylinder 1252*. These two pistons are rigidly connected by a rod 127 and the slide valve 120 is attached to this rod. The supply of fluid pressure to the outer end of cylinder 125 is `controlled by a pin valve 128, which, in

turn, is controlled by an armature 10a operated by an electromagnet 10. When the magnet 10 is energized, -the valve 128 is in the position shown inthe drawing, so that the outer end of cylinder 125 is connected through port 129 and `131 with the valve chamber 121, and so is supplied with iiuid'.

pressure. When magnet 1() becomes de-energized valve 128 will be reversed by means of spring 132, so that the port 129 leading to cylinder 125 will be disconnected from the valvechamber 121 and willbe opened to atmosphere through port 130.

:The outer end of cylinder 125a is controlled by a valve 128s, which, in turn,is actuated by armature 9an of electromagnet 9,

these parts being similar to the parts associated with cylinder 125.

As shown in the drawing, magnetV 10 is energized and magnet `9 is de-energized, so

-that cylinder 125 is connected with fluid pressure and cylinder 125a is opened to atmosphere. Iistons1'26 and 126a are, therefore, in such positions thatv the keps are in locking positions. lWhen it is Vdesired to unlock the cage 1, magnet 9 will be energized and magnet 1() will be tie-energized, so that lthe pistons 126 and 126a will be moved upwardly, as shown in Fig. 4, whereupon slide valve 120 will be reversed to reverse the position of piston 116 in the cylinder 115.

In order to lock the slide valve 120 in its extreme positions, the `back of this valve is provided with notches lco-operating with a plunger v134 which is pressed' inwardly toward the slide valve bya spring 135.

Referring now to Figs. 5, 6,7 and 8, the automatic axle counter `16 comprises two star `wheels fixed to a shaft l156 and each having six arms positioned for vengagement with the axles of the tubs 6. Each axle rotates lthese star wheels through one-sixth of a revolution, so that three tubs will cause a complete revolution of the wheels. The inner side of each star wheel 16 is provided with a hub 137 having anotch or recess 137a as best shown in Fig. 8, and co-operating with this notch `is a dog 138 which is attached to a rod 139 and is biased by a spring 140 to such position that the dog enters notch 137a when the two are in register. It follows from this that after the dogv 138 has been released, three tubs may pass the counter without being impeded, but that after the sixth axle passes this counter the dog 138 will be drawn into the notch 137a by the spring 146, so that the passage of further tubs will be prevented.

'The rod 139 is connected with a second rod 141 which is attached to a crank 142 on a transverse rod 143. ri`he outer end of this latter rod carries al crank 144 which is bent, as shown in Fig. 7 to bring the tree end in the path ot a bent crank 145 pivotally mounted on the stationary portion 155 of the pit head mechanism. Fivotally attached to the crank 145 is a rod 146, which, in turn, is connected with a piston 147 operating in a cylinder 148 of the unlocking motor mechanism 18. The outer end of cylinder 148 'is connected with atmosphere through a port 151 or with a source of tiuid pressure 150, depending` upon the position oi' a pin valve 149 which is actuated by an armature 152 of an electromagnet 153. When this magnet is cle-energized the pin valve occupies the position in which it is shown due to the influence of a spring 157, so that cylinder 147 is then connected with atmosphere through port 151. When magnet 153 becomes energized, pin valve 149 is reversed so that cylinder 148 is disconnected from atmosphere and is connected with the fluid pressure vpipe 150, so that this piston and the rod 46 are then moved to the left, as viewed in Fig. 5. This causes crank 145 to engage with crank 144, thereby rocking the shaft 143 in such direction as to move rods 141l and 139 to the left, thereby moving the dog 138 out of the notch 137a and so releasing the star wheels of the counter 16. ritter one axle has passed this countei magnet 153 may be de-energized, but the dog 138 will not interfere with the passage of subsequent axles until three tubs have passed over the counter.

The contacts 20 or 21, shown in Fig. 1, are .contained in a box 136 and are actuated by a crank 154 which is shifted by the upper end oi"- crank 144 when the motor 18 is operated to release the counter. Contacts 20 and 21 are in the position illustrated in Figs. 1, 2 and 3 only when the counter is locked. At all other times thesev contacts are reversed.

As best shown in Figs. 5 and 7, the axle counter 16 is mounted upon the hoisting cage 1, whereas the motor mechanism 18 andthe circuit controller box 136 are mounted upon the stationary portion 155 of the pithead mechanism, so that the electrical conductors for the control of the motor and for the contacts 20 and 21 are not attached to the cage.

Refer-ring now to Fig. 9, the automatic axle counter 40 comprises a star wheel 158 fixedV to a shaft 163`which is mounted to rotate .in a suitable frame 162. rllhe star wheel 158 is provided with six arms each positioned for engagement with the axles of the tubs 6, so that this star wheel makes one complete revolution for each three tubs. Fixed to the star wheel 158 is a circular cam 159 having a Arecess 159'El at one point in its periphery. Pivotally mounted in the trame 162 is a dog 160 having a roller co-operatingy with thesurtace of the cam 159.` A. rod 161 is pivot-ally connected-with the dog 160, and this rod and dog are biasedto the right as viewed in Fig. 9 by a spring 161 so vthat when the recess 159EL registers with the roller on the dog 160 this dog will fall into the recess as shown in the drawing. The indication contacts 40 are operatively connected with the dog 160 so that these contacts are in one position after six axles have passed and are in the other position until six more axles have passed.

Referring now to Fig. 10, the automatic axle counter 48r is similar to lthe counter shown in Fig.` 9, with the following exceptions: rl'he star wheel which is designated 164 in Fig. 10 is provided with 12 arms, so that this wheel makes a complete revolution for six tubs. The cam which is here designated 165 comprises two sections, each of which is semi-circular in contiguration, the radius of one section being greater than the radius ot the other section. 1t

`follows that during one half of the revolution of the star wheel, that is, during the passage of three tubs, the dog 160 will occupy one position and during the passage ol the next three tubs this dog will occupy another position, the result being that contact 48 will be reversed after the passage ot each three tubs.

Referring now to Figs. 11, 12 and 13, the power actuated ram 51 comprises a cylinder 167 containing a plunger 168 provided with a piston 169. The outer end of plunger 168 is provided with a crosshead 170, in which is journaled a shaft 173 carrying two wheels 174 which roll on suitable guides 181 located in the trackway. Pivotally mounted on the shaft 173 is a driving arm 171, the tree end of which is provided with a concave face 171a adapted for co-operation with theltub axlesy172. rThe driving arm 171 isi-biased by a spring 176 to such posi- Een tion that it will engage with the axles 172, this spring being seated in the crosshead 170 and coacting with a shoulder 171b on the driving arm 171. Upward movement of the arm 171 is limited by a stop 175 in the crosshead 170. The cylinder 167 is so located in the trackway that it will be cleared by the tub axles, and it will be obvious that each axle passing over the ram will `depress the arm 171 so that this arm will not interfere with the passage of the tubs.

As shown in Fig. 13, a port 180 enters the cylinder 167 at a point to the right of the extremeoutward position of the piston 169. This port 18() leads to a source of fluid pressure so that the supply of pressure at this point in the cylinder is constant. The left-hand end of cylinder 167 is connected with fluid pressure through a 'pipe 178 or with atmosphere through a port 179, depending upon the position of the pin valve 177 which is controlled by the armature of a magnet 53, these parts being similar to the parts associated with motor 18, shown in Fig. 5, and explained hereinbefore.

When magnet 53 is cle-energized, the lefthand end of cylinder 167 is connected with atmosphere and piston 169 is then driven to the left due to the action of the fluid pressure admitted to the cylinder through the port 180. When magnet 53 becomes energized, however, iiuid pressure is admitted to the left-hand end of cylinder 167, whereupon the piston 169 and rod 168 are shifted to the right owing to the fact that the entire left-hand face of piston 169 is exposed to fluid pressures whereas the effective area of the right-hand face of this piston is considerably reduced because of the presence of the rod 168.

The power actuated ram, illustrated in Figs. 11, 12 and 13 and just described, is disclosed and claimed in my United States Patent No. 1,407,253, granted Feb. 21, 1922, for power operated rams.

Referring now to Figure 2 of the drawings, it will be seen that in addition to the electro-magnetic valve actuated mechanismand indication contacts already described, the electrical portion of the apparatus comprises a manually operated control lever 61 adapted to occupy one or other of three different positions, indicated at N, C, R The lever 61 is operatively connected to a shaft 62 carrying a number of switch elements 63, 64, 65. 66, 67 and 68 and two interlocking members 69 and 70 provided with release magnet 71, 72 respectively. The switch elements are utilized, as will appear hereinafter, to control the various elements shown in Fig. 2 and referred to collectively in certain of the appended claims as cage governing means.

The construction of the switch elements 63 to 68 inclusive is suchl thatthe switch 64-is closed whenthe lever 61 is either in its N position or in its C position. The switches 65 and 66 are closed when the lever 61 is in itsC position or in its R position` The switch 67 is closed when the lever 61 is in its R position only and the switches 63 and 68 are closed only when the lever 61 is in its N position.

rThe locking devices indicated at' 69 and are so constructed that the former will prevent the lever 61 from being moved from the C position to the R positionuntil themagnet 71 is energized. The locking device 70 is similarly arranged to prevent movement of the lever 61 from its C position to its N7 positioniuntil the corresponding magnet 7 2- is energized. Y

The electric'interlocking system also includes a number of relays indicated at 73, 74, 75, and 76 the armatures of these relays controlling a number vof electrical circuits as will be hereinafter described with reference to this figure of the drawing.

Electrically actuated indicators A, B, and D are also provided for the purposefof notifying the operator that certain conditions of the various elements are obtained. The general method of operation of the decking plant above described is as-'followsz The hoisting cage 1 is raised to thev surface carrying with it six tubs or trucks three on each deck of the cage. As the cage rises towards its final position the gate 22 is lifted and the cage is eventually locked in the unloading position by means of the keps` 7. The empty tub hoist 3 has previously been placed in position and contains six empty` tubs or trucks three 0n Aeach deck ready for transfer-to the hoisting cage 1. The full tub hoist 2 is also inthe position shown in Figure 1`ready to receive the full tubs from the hoisting cage 1.A

Assuming that the hoisting cage 1 and the empty and full hoists 3, 2 are in proper position, the axle stops or counters 18,`19,.27,

28 are unlocked and the rams 51, 52l are started into operation and drive the empty tubs contained in the hoist 3 into the hoisting cage 1 thereby displacing the full tubs contained in the cage 1 which are driven on to the two decks of the full tub hoist-2. The

lcage 1 is now free to descend andthe empty tubs contained on the lower deck 39 of the f alongthe track 47. The rams 51 and 52 after completing their forward movement to transiter the empty tubs from the hoist 3 to the cage l automatically return ready tor the next charging operation.

rlhe various electrical circuits involved during'the operation above referred to will now be described in detail with reference 'to Figures 2 and 8 oi"- thedrawings, Figure 2 showing the complete system ot electric conductors and switches employed and Figure 3 showing in simplified form the circuits completed at each stage ot the operation.

Assuming that one complete cycle of operations has been performed, the hoisting cage l containing the empty tubs is reacy for lowering into the pit and the tub hoists 2 and 3 are in the positions shown in Figure l. The control lever 6l is assumed to be in its N position and the following cirw cuits are completed: a circuit indicated at (a) in Figure 3 from the positive terminal 77 through indication contacts 59 and 60, upper indication switch l5, upper indication switch 14;, right hand indication switch 2l, right hand indication switch 20, the switch ot axle counter 40, lower indication switch 43, the switch of axle counter lil to the point T8. At this point the circuit branches into two parallel circuits, viz, one through right hand indication switch ll, conductor 79 locking magnet 'Z2 to negative terminal 80, a branch circuit being completed from conductor 79 through control switch 68 and indicator A to the negative terminal 8l. rlFhe other parallel circuit trom the point 78 is through control switch Gli and valve actuating magnet l0 of the liep motor 8 to the negative terminal 82. rllhe completion ot this circuit causes the indicator A to give the indication all clear to lower, this indication being only given it the various indication contacts above described are closed as will only be the case if the hoisting cage l is in its proper position, the axle lcounters locked, the leps withdrawn from under the cage and the rams 5l and 52 in their fully retracted position. Another circuit indicated at (c) in Figure 3 is also completed from the positive terminal 88 through the control switch 68 relay winding 78 to the negative terminal l0?. The relay 73 being thus energized its two armatures are held in their closed position. rlhe hoisting cage l can now be lowered and refilled at the bottom oi2 the shaft with full tubs or trucks which are subsequently raised to the surface. lWhen the hoisting cage lY has reached the surface, lifted the gate 22 and closed the indication contact 23, the control lever 6l may be movedY to its C position with the result that the following circuit (indicated at (f) in Figure is completed: from the positive termi-nal 84 through indication contactv 23, conductor 85 control switch 65,

actuating magnet 9 of the kep motor 8 to the negative terminal 82. F luid under pressure is thereby admitted to the liep motor 8 to cause the latter to place the keps "Y under the cage l and when this movement ot the lteps is completed closing the lett hand indication contact ll an indication circuit (shown diagrammatically at (o) in Figure $3) is completed as `follows: from the positive terminal 86, left hand indication switch 1l, conductor 87, indicator B to negative terminal 88. rlhe indicator B thereupon gives the indication keps under cage.

further circuit is also completed from conductor 87 through lower indication switcl- 45 indication switches-24 and 37 conductor 89 lowe armature of the relay 73, control switch 68 and through the actuatinV agnets ot the Jfour axle counter unloclsiing motors 18, 19, 29, 30 for the axle counters l, 17, 2i', 28 respectively to the negative terminals 90.

lt will be observed that the original energizing circuit (o) for the relay 78 through the control switch 68 is broken at this switch when 'the lever 6l is moved into its C position. A maintaining circuit for the relay is however provided (indicatef (d in Figure 3) from positive terminal 9i elay is thus maintained energized so ong indication contacts lll, are closed.y l/'Vhen the afle counters 16, 17, 27, 28 have been properly unlocked the corresponding indication contacts20 2l, 8l` 32 are closed ant a branch circuit from the lower armatur of the relay 73 is completed through conductor 92.r left hand indication switch Si conductor 9?), left hand indication switch 2O; conductor 94, middle indication switch conductor 957 lett hand indication switch 2 i the actuatin magnet of the indicator to the negativ-e terminal 96 and throufh tac i'uiloclring magnet 7l to the negative minal 97. rllhe indicator D now gives the indication ready to ram and the unlocking magnet 7l being energized the control lever 6l is free to be moved to its l posiH tion in which the vtollof'vving circuit indi cated at (e) in Figure 3 is completed: from the positive terminal 88 through the control switch 67, conductor 98 to the poin where the circuit branches through the lower armatures of the relays 71h T5 `to con ductors 1005 lOl leadi-ir through the valve actuating magnets 58T 5s? respectively negative termi al The control electro-- magnets ot the rams 5le 52 being thus energized the rams are operated and move forward to drive the tubs contained on the two declrs o the empty tub hoist 3 on to tle correspon r l l decis ot the li-oistinO cage l thereby dislpla-cing the full tubs 6 from M Lcacai lbroken ,and the armatures of these relays therefore move into their open position in which the circuit (e) through the actuating -magnets 53, 54 of the rams is interrupted at the lower armatures of the relays 74, 75. It will be understood that the circuits originally energizing the relays 74, through the indication contacts 31, 2O and 32, 21 have already been interrupted by the unlocking of the corresponding axle counters 27, 16, 28, 17 with the result that when the circuits through the indication contacts 57, 58 are interrupted by the passage of the ram heads, the relays 74, 75 will permit their armatures to fall and thereby cle-energize the actuating magnets 53, 54 or the rams 51, 52 which consequently return automatically to their retracted position.

The passage of the axles of thetubs over the indication contacts 14, 15 has caused circuit (d) to be interrupted by the opening of these indication contacts, with the result that the relay 73 is cle-energized and its armatures move to their open position.

As soon as the total number of tub axles has passed over the axle counters the counters 40, 41 re-establish the indication circuits which were interrupted during the passage of the tubs and the axle counters 16, 17 ,-27, 28 are again locked automatically.

The control lever 61 may now be moved to its C position in which circuit (a) through control switch 64 and valve actuating magnet 10 of t-he kep motor 8 is completed. 1t should be pointed out that in addition to closing of control switch 64 by lever 461 in its C position, the kep motor can be actuated over circuit (ai) only if the hoisting cage 1 is in its proper position, the axle counters locked, the back stops 12 and 13 in their normal positions, and the rams 51 and 52 withdrawn clear of the cage. y

The kep motor 8 is thereupon operated and withdraws the keps 7 from underneath the hoisting cage 1. As soon as the keps are fully withdrawn right hand indication contact 11 is closed and the branch of circuit (a) including the locking magnet 72 is completed, this magnet being energized and releasing the locking device 70, which permits the control lever 61 to be returned to its N position in which the branch circuit (a) through the indicator A and circuit (c) are again completed` as above described and the signal indication alliclear to lower7 is given. 2

The circuits indicated at (g) and (72,) in

Figure 3 controlling the full tub hoist 2 and the empty tub hoist 3 respectively operate as 'follows'r- The axle counter 40 will be in its normal or closed position after the three tubsij'rom the upper dec-lr 4 of the hoisting cage 1 have passed lover the axle counter 40 and the `back stop 42, the indication contact 43 being reclosed aiter the last axle has passed.

The axle counter 48 will also be in one ot its two closed positionsy (shown in' dotted lines in Figure 3) after the six axles of the tubs `on the lower deck 39 have passed outl along the track 47 and over the counter 48.

The indication contact 46 being in its closed position owing to the hoist 2 being in its upper position the circuit (g) will be completed from the positive terminal '103 through indication contacts 40, 43, 46 axle counter switch 48, the valve actuating magnet 50 of the fluid pressure device 49 to the negative terminal 104. The device 49 is thereby started into operation and permits the hoist 2 to descend until the upperdeck 38 of the hoist is level with the track 47, whereupon 'the indication contact 46 is opened and the circuit (g) interrupted.

The three tubs on lthe upper-deck of the hoist then pass outof the hoist onl to the track 47 and when all six axles have passed the axle counter 48 attains the position shown in full lines in Figure 3. lThe hoist 2 being relieved of the weight of the three tubs on the deck 38 rises under the action.

of balance weight mechanism or 'its equivaf lent to the position shown in FigureA l, but the circuit (g) still remains interrupted at the axle counter contact 48 although the contact 45 is reclosed when the hoist 2 attains its upper position.

Referring nowv to the control circuit (h) for the empty tub hoist 3, it will be evident that this circuit is completed from the posi tive terminal through indicationv contacts31, 35, 55, 56, 36, 32, the relay winding 76 to the negative terminal 106. The indication contacts above referred to are closed only when the rams 5l, 52 are fully retracted not only from the hoisting cage 1 but also from the hoist 3, and are at rest in their inoperative position. lVhen this is the case the relay 76 isenergized and closes control circuits for the operation of the hoist 3 which may be of any suitable character' and need` not be described or illustrated.

It will be understood that the invention in its broader aspect is not liinitedto the arrangements or connections above described which merely constitute one form of installation embodying the invention..` In

other embodiments thereof a greater or less degree of automatic operation may be provided for instead of the manually controlled operation herein shown y and described. Modifications in these and other respects may obviously be made Without exceeding Vthe scope of the invention.

Having now described my invention, What I claim as new and desire to secure by Letters Patent is 1. A colliery decking plant comprising a hoisting cage, indication means for giving a cage-lowering signal, a back stop in said cage having operative and inoperative positions, and means for preventing said indication means from giving said signal unless said stop is in the operat-ive position.

2. A colliery decking pla-nt comprising a hoisting cage, a back stop on said cage for preventing tubs from moving out of the cage backvvardly, and indication means controlled by said back stop.

3. A colliery decking plant comprising a hoisting cage, indication means for giving a cage-lowering signal, an axle counter operated by tubs passing out of said cage, and means for preventing said indication means from giving said signal until a given number of tubs have left the cage.

4. A colliery decking plant comprising a hoisting cage, an axle counter operated by tubs passing out of said cage, and indication means controlled by said counter.

5. A colliery decking plant comprising a hoisting cage, indication means for giving a cage-lowering signal, a ram on the plant deck for moving tubs in said cage, and means for preventing said indication means from giving said signal unless the ram is clear ot the cage.

6. A colliery decking plant comprising a hoisting cage, indication means for giving a cage-lowering signal, an axle counting de,- vice operated by tubs passing out ot said cage and arranged to lock after a given number of tubs have passed and thereby prevent the passage ot more tubs, and means for preventing said indication means from giving said signal unless said counting device is locked.

7. A colliery decking plant comprising a hoisting cage, an axle counting device operated by tubs passing out of said cage and arranged to lock after a given number of tubs have passed and thereby prevent the passage of more tubs, and indication means controlled by said counting device.

"8. A colliery decking plant comprising a hoisting cage, a full-tub hoist adapted toreceive tubs fromv said cage, an axle counter operated by tubs entering said hoist from said'cage, and indicationv means controlled saidfcounter.

' colliery decking plant comprising a hoisting cage, a full-tub hoist adapted'to iieceive'tubs `from 'said' cage, a back stop on said full-tuby hoist, and indication means controlled by said back stop.

l0. A colliery decking plant comprising a hoistingV cage, meansfor locking said cage nsoaeei at the plant deck, a ram for moving cars ont of said cage, and means for preventing release of said locking means unless said rain is clear of the cage.

11. A colliery decking plant comprising a hoisting cage, locking means for said cage, a ram on the deck plant for causing movement of tubs in said cage, and means con trolled by the position oit said ram for re leasing said locking means.

12. A colliery decking plant comprisingl a hoisting cage, means for locking said cage at the plant deck, a ram tor moving tubs out of said cage, and means for releasing` said locking means only When said ram is clear of the cage.

13. A colliery decking plant comprising a hoisting cage, means 'for locking said cage at the plant deck, aback stop in said cage capable of operative and inoperative positions, and means for preventing release ot said locking means unless said back stop is in the operative position.

14. A colliery decking plant comprising` a hoisting cage, a back stop in said cage, and locking means for said cage controlled by the position of said back stop.

l5. A colliery decking plant comprising a hoisting cage, means for locking said cage at the plant deck, an axle counter operated by tubs passing out of said cage, and means for preventing release of said locking means unless a given number of tubs have passed out of the cage.

16, A colliery decking plant comprising a hoisting cage, an axle counter in said cage, and locking means for said cage controlled by said axle counter.

17. A colliery decking plant comprising a hoisting cage, means for locking said cage at the plant deck, an axle counter operated by tubs passing out of said cage and arranged to lock after a given number of tubs have passed and thereby prevent the passage of more tubs, and means for preventing release of said locking means unless said counter is locked.

18. A colliery decking plant comprising a hoisting cage, an axle counter operated b v tubs passing out of said cage and arranged to lock after a given number of tubs have passed and thereby prevent the passage ot more tubs, and locking means for said cage controlled by said counter. Y

19. A colliery decking plant comprising hoisting cage., a ull-tub hoist adapted to receive tubs from said cage, an axle counter1 operated by tubs entering said hoist from said cage, and locking means :tor said cage controlled by said counter. i 2O.v A colliery decking plant comprising a hoisting cage, a full-tub hoistadapted to receive tubs from said cage, a back stop on said full-tub hoist, and locking means for said cage controlled by said back stop.

2l. A colliery decking plant comprising a hoisting cage, an axle back stop for said cage, a counter operated by tubs passing out of said cage, a ram on the plant deck for moving tubs in said cage, and locking means for sa d cage controlled by said back stop, counter and ram.

22. A colliery decking plant comprising a hoisting cage, an axle back stop for said cage, a counter operated by tubs passing out of said cage, ram on the plant deck for moving tubs in said cage, locking means 'for said cage, and indication means controlled b v said back stop, counter, ram and locking means.

A colliery decking plant comprising a hoisting cage. a gate 'lor said cage, and means controlled by said gate for locking said cage at the plant deck.

24. A colliery decking plant comprising a hoisting cage, means for locking said cage at the plant deck, a fluid pressure motor tor operating said locking means, a manually operable lever, and means for controlling said motor by said lever and by vthe position of said cage,`

25. A colliery decking plant comprising a hoisting cage, means for locking tubs in said cage, and means for preventing release oli said locking means unless the age is in proper position at the plant deck.

26. A colliery decking plant compi-'sing a hoisting cage, means for locking said cage at the plant deck, a back stop for preventing backward movement or tubs from said cage,

locking means for preventing forward movement of tubs from said cage, and means for preventing release of said locking means unless the cage is locked at the plant deck and said back stop is in operative position.

27. A colliery decking plant comprising hoisting cage. a back stop :tor the tubs in sa'd cage, and an axle counter tor the tubs in said cage controlled by the position of said back stop.

Q8. A collieryv decking plant comprising a hoisting cage, an empty-tub hoist and a Ylulltub hoist, and means for preventing the passage of tubs out vof said cage unless the cage and both hoists are in proper positions at the plant deck.

Q9. A colliery decking plant comprising a hoisting cago, means for locking tubs in said ca je, a manuallj.7 operable lever for control of said locking means, and means tor turtlier controlling said locking means by the position ot' said cage.

30. A colliery decking plant comprising a hoisting cage, locking means for preventing forward movement of tubs from said cage, a lever having normal and middle positions, a back stop for preventing backward movement of tubs from said cage, a relay, a pick-up circuit Jfor said relay closed Whensaid lever is in normal position, a holding forward movement of tubs from said cage,v

an indicator for giving a ready to ram7 signal, and means for preventing said indicator from giving said signal unless said locking means is released.

33. A colliery decking plant comprising a.

hoisting cage, locking vmeans forl preventing forward movement of tubs from said cage, and an indicator controlled by said locking means.

34. A colliery decking plant comprising a hoisting cage, locking means for preventing 'forward movement of tubs from said cage, and means controlled by said locking means and operative only When-the latteris released for giving a ready to ram signal.

A colliery decking plant comprising a hoisting cage, a ram for moving tubs out of said cage, locking means for preventing torivard movement of tnbsfrom said cage, and means for preventing operation of said ram unless said locking means is released.

36. A colliery decking plant comprising a hoisting cage, a stop for preventing backward movement of tubs from said cage, and a ram controlled in part by said stop for moving tubs out of said cage. i

37. A colliery decking plant comprising a hoisting cage, locking means for prevent ing 'forward movement of tubs from said cage, anc a ram controlled by said locking means for moving tubs out ot said cage.

A colliery decking plant comprising a hoisting cage, a ram for moving tubs out of said cage, and means for preventing operation o'f said ram unless said cage is in proper position at the plant deck.

539. A colliery decking plant comprising a hoisting cage, means for locking said cage atV the plant deck, a ram for moving tubs out or" said cage, and means for preventing operation of said ram unless said cage is locked at the plant deck. l

4:0. A. colliery decking plant comprising a hoisting cage, an empty-tub hoist for delivering tubs to said cage, and a full-tub hoisty tor receiving tubs from said cage, a.

ram for moving empty tubs from said empty-tub hoist to said cage and full tubs trolnsaid cage toy fulbt'tib hoist, and means ro-r preventingop'eration of said ram unless said cage and hoists are all in proper registering positions at the plant deck.

-llz A colliery decking plant comprising` a hoisting cage, a ram tor moving tubs out ot said cage and arranged to automatically assume its retracted position, a motor tor iuoving said ram to projected position, a relay, a counting device operated by tubs passing out ot said cage and arranged to lool; after a given number of tubs have passed, a pick-up circuit tor said relay closed only ivhen said counting device is released, a holding circuit for said relay closed when the relay is closed until said ram reaches its fully projected position, and means for supplying energy to said ram motor when said relay is closed.

42. A colliery decking plant con'iprising a hoisting` cage, a ram tor moving tubs ont ot said cage and arranged to automatically assume its retracted position, a motor tor moving said rain to projected position, a counting device operating by tubs passing out ot said cage and arranged to lock after operation by a given number ot tubs, means for releasing said device, and means for snpplying` energy to said motor when said device has been released and thereafter discontinuing such supply when the ram reaches its fully projected position.

43. A colliery deckingplant comprising,l a hoisting cage, a ram for moving,` tubs out ot said cage, a manually operable lever llaving normal, middle and reverse positions, arelay, a piek-up circuit 'for said relay closed only when said lever is .in normal position, a back stop for said cage, a holding' circuit for said relay closed only vvnen said back stop is in operative position, locking means for said cage operable only in middleto-reverse positions oitI said lever, locking means for preventing` Ylorivard movement of tubs out of said cage, means tor releasing` said locking` means only when said lever is in n'iiddle-to-reverse posi ions and said relay is closed and said cage in proper position at the plant deelt ano is locked, leve-rlocliing means for preventing movement ol.l said lever to tull reverse position, means tor releasing` said lever-locking means only when said cage is in proper position at the plant decl: and is locked, said relay is closed, and said tub locking means is released, and means tor operating said ram only when said lever is in tull reverse position.

44. A colliery decking plant comprising; a hoisting` cage, a rain tor moving tubs out ot said cage, a manually operable lever having normal, middle and reverse positions, a relay, a pick-up circuit for said relay closed only When said lever is in normal position, a back stop for said cage, a holding circuit for said relay closed only when said back stop is in operative position, locltinp; means for said cage operable only in middle-tomossel reverse positions oit said lever, looking means Vtor preventing,v fore/'ard movement ot tubs out oli said cage, means ior releasing` said locking,l means only 'when said lever is in middle-to-reverse positions and said relayy is closed and said cage is in proper position at the plant deelt and is locked, lever-loci;- ingv means tor preventing movement oit aid lever to tull reverse position, means rer releasing," said lever locking means onlv when said. tnb locking means is unlocked, and means operable only ivlien said lever is in Vlull reverse position tor actuating said rain..

45. A colliery decking plant comprising;y a hoisting cage, a ram for moving tubs out ot said cage, a manually operable lever harina' normal and reverse positions, a lock for preventing inovenient ot said lever to 'tall reverse position, means operable only when said lever is in linll reverse position tor actuating' said rain, locking means 'tor preventing' forward movement ol' tubs out ot said aigre, and means tor controlling said lever loclt by sait t b locking means.

,l colliery decking plant cmnprisizni a hoistingcage, a ram for moving tubs ont ot said cage, a manually operable lever having normal and rever e positions, a loclt ttor preventing movement ot said lever to full reverse position, means operable only vviien said lever is in toll reverse position for matar-,tingl said ram, means tor locking' said cage at the plant deelt, and means tor controlling said lever lock by said cage locking means,

47. A colliery decking` plantv comprising,l a hoisting cage, a ram for moving tubs out of said cage, a manually operable lever having normal and reverse positions, a lochV for preventing movement ol said lever to full reverse position, means operable only When said lever is in toll reverse positil'in tor actuatingsaid ram, and meaiis for con trolling;v said lever lock by the position ot said cape.

A. colliery decking` plant comprising a hoisting' cage, a ram tor moving` tubs out ot said cage, a manually operable lever hav-- ing` norn'ial and reverse positions, a lock for preventing; movement ot' said lever to tull reverse position, means operable only nhen said lever is in tull reverse position tor actuating;- said ram, and means to pievi-mtingi-r rclease ot said lever lock unless said cage is in proper position at the plant decl; and is locked.

49. it colliery decking plant comprising.Y a hoisting` cage, a ram 'tor moving; tubs out of said cape, a manually operable lever having;` normal and reverse positions, a lock 'tor preventing movement ot said lever to full reverse position, means operable only n'hen said lever is in full reverse position tor aetuatingr said ram, means tor lockingd said at the plant deelt, and means tor pre-- tin llfi

venting release of said lever look unlessY said cage is locked,

50. colliery decking plant comprising hoisting cage, a ram Jfor moving tubs out of said cage, manually operable lever having normal and reverse positions, a lock for preventing movement of said lever to full reverse position, means operable only ivlien said lever is in full reverse position :tor actuating said ram, and means for preventing release of said lever lock unless said cage is in proper position at the plant deck.

5l. colliery decking plant comprising a hoistingcage, a ram for moving tubs out of said cage, a manually operable lever hai# ing normal and reverse positions, a lock for preventing movement of said lever to full reverse position, means operable only when said lever is in full reverse position for actuating said ram, a back stop for saidv cage, and means for controlling said lever lock by said back stop.

52. A colliery decking plant comprising a hoisting cage, a manually7 operable lever having a normal position, a lever lock for preventing movement of said lever to normal position, cage governing means operable only When said lever is in normal position, means for locking said cage, and means for preventing release of said locking means unless said cage is unlocked.

53. A colliery decking plant comprising a hoisting cage, a manually operable lever having a normal position, a lever lock for preventing movement of said lever to no-rmal position, cage governing means operable only When said lever is in normal position, means for locking said cage, and means for controlling said lever lock by said cage locking means.

54. A colliery vdecking plant comprising a hoisting cage, a manually operable lever having a normal position, a lever look for preventing movement of said lever to normal position, cage governinff means operable only ivlieii said lever isV in normal position, a counter operated by tubs passing out of said cage, and means for preventing release of said lever lock until said counter has been operated a given number of times,

55. A colliery decking plant comprising` a hoisting cage, a manually operable lever having a normal position, a lever lock for preventing movement of said lever to normal position, cage governing means operable only when said lever is in normal position, a counter operated by* tubs passing out of said cage, and means Yfor controlling said lever lock by said counter. i

A colliery decking plant comprising a hoisting cage, a manually operable lever having a normal position, a lever lock tor preventing movement of said lever to normal position, cage governing means operhaving normal position, a lever lock for preventing movement of said lever to normal position, cage governing means operable only when said lever is in normal position,

a deck for receiving tubs from said cage, a back stop for said deck, and means for preventing` release of said lever lock unless said back stop is in stopping position.

58. A colliery decking plant comprising a hoisting cage, a manually operable lever having a normal position, a lever lock for preventing movementJ of said lever to normal position, cage governing means Operable only When said lever is in normal position, locking-means for preventing` tubs 'from leaving said cage, and means for preventing release of said lever unless said locking means is locked in operative position.

59. A colliery decking plant comprising a hoisting cage, a` manually operable lever having a normal position, aV lever lock `for preventing movement of said lever to normal position, cage governing means operable only When said lever is in normal position, a counter operated by tubs leaving said cage and'arranged to lock automatically and prevent the passage or' further tubs after a given number of tubs have passed, and means for controlling said lever lock by said counter.

60. A colliery decking plantv comprising a hoisting cage, a manually operable lever having a normal position, a lever loc-k for preventing movement of said lever to normal position, cage governing means operable only when said lever is in normal position, a counter operated by tubs leaving said cage and arranged to lock automatically and so prevent the passage oi v:liurther tubs after al given number of tubs have passed, and means for preventing 'release of said lever lock unless said counter is locked.

6l. A colliery Vdecking plant comprising a hoisting cage, a manually operable lever having a normal position, a lever lock for pre-v venting movement of said lever to normal position, cage governingmeans operable only when said lever is in normal position, a back stop for said cage, and means for controlling' said lever lock by said back stop.

62. A colliery deckingplant comprising a hoisting cage, a manually operable levier havling a normal position, a lever loclvfor preventing movement of said lever to normal position, cage governing means operable only when said lever is in normal position, back. stop for said cage, and. means-for iio preventing release of said lever lock unless said back stop is in operative position.

63. it. .colli f decking plant comprising a hoisting cage., a manually operable lever having a normal position, a lever lock for preventing movement of said lever to normal position, cage governing means operable only when said lever is in normal position, a. ram for moving tubs out of said cage, and means for controlling said lever lockv by the posi Non of said ram.

64. A colliery decking plant comprising a ioisting cage, a manually operable lever havng a normal position, a lever lock for preventing movement of said lever to normal position, cage governing means operable only When said lever is in normal position, a ram for moving tubs out of said cage, and means for preventing release of said lever lock unless said ram is clear of the cage.

65. A colliery decking planty comprising full-tub cage having two decks and normally occupying such position that one of its decks registers With the plant deck, mechanism for shifting said cage to such position that its other deck registers with saidv plant deck, a counter operated by tubs entering said cage, and means for preventing operation of said shifting means until a given number of tubs has passed said counter.

66. A colliery decking plant comprising a full-tub cage having two decks and normally occupying such position that one of its decks registers with the plant deck, mechanism for shifting said cage to such position that its other deck registers With said plant deck, a counter operated by tubs entering said cage, and means for controlling said shifting mechanism by said counter.

67. A colliery decking plant comprising a full-tub cage having tivo decks and normally occupying' such position that one of its decks registers with the plant deck, mechanism for shifting said cage to such position that its other deck registers with said plant deck, a back stop for said cage, and means for preventing operation of said shifting mechanism unless said stop is in operative position.

68. A colliery decking plant comprising a full-tub cage having tivo decks and normally7 occupying such position that one of its decks registers With the plant deck, mechanism for shifting said cage to such position that its other deck registers with said plant deck, a back stop for said cage, and means for controlling' said shifting mechanism by the position of said back stop.

69. A colliery decking plant comprising a full-tub cage having tivo decks and normally occupying such position that one of its decks registers With the plant deck, mechanism for shifting said cage to such position that its 'other deck registers with said plant deck, a counter operated by tubs leaving said cage,

incassi.

and means for preventing operation of said shifting mechanism until said counter has been operated a given number of times.

T0. A colliery decking plant comprising a full-tub cago 'having two decks and normally occupying such position that one of its decks registers with the plant deck, mechanism for shifting said cage to such position that its other deck registers 'with said plant deck, a counter operated by tubs leaving said cage, and means for controlling said shifting mechanisn'i by said counter.

7l. A colliery decking plant comprising a full-tub cage having tivo decks and normally occupying such position that one of its decks registers with the plant deck, mechanism for shifting said cage to such position that its other deck registers with said plant deck, and means for controlling said shifti mechanisn'i by the position of said cage.

72. A colliery decking plant comprising a full-tub cage having two decks and normally occupying such position that one of its decks registers with the plant deck, mechanism for shifting said cage to such posit-ion that its other deck registers with said plant deck, means for counting the tubs leaving said cage, and means for controlling said shifting mechanism jointly by said counting means and by the position of the cage.

73. A colliery decking plant comprising a full-tub cage having two decks and normally occupying such position that one of its decks registers With the plant deck, mechanism for shifting said cage to such position that its other deck registers with said plant deck, a first contact closed when the cage occupies its normal position and open When the cage is in shifted position, a second contact open when the cage is in normal position and closed when the cage is in shifted position, a third contact closedV only after all the tubs accommodated by the first deck have left the cage, a fourth contact closed only after all the tubs acconunodated by the second deck have left the cage, and a circuit for the control of said shifting mechanism and having tvvo branches one of which includes the first and third contacts in series and the other of which in cludes the second and fourth contacts in series.

1l, A colliery decking plant comprising a full-tub cage having tivo decks and normally occupying` such position that one of its decks registers With the plant deck, mechanism for shifting said cage to such position that its other deck registers with said plant deck, and means for setting said mechanism into operation after a viven number of tubs have left the first deck of the cage and releasing said mechanism after a given number of tubs have left the second deck of the cage.

75. A colliery decking plant comprising a full-tub cage having tivo decks and normally occupying such position that one of its decks registers with the plant deck7 and means operating after a given number ci' tubs have left said one deck to shift said cage 'to such position that its other deck registers with the plant deck and to hold it there until a given number of tubs have leftV the second cage deck.

76. A colliery decking plant comprising a movable empty-tub cage, a back stop 'for tubs in said cage, and means for controlling the movement of said cage by the position of said stop.

77. A colliery decking plant comprising a movable empty-tub cage, a back stop for tubs in said cage, and means for preventing movement or" said cage unless said stop is in operative position.

7 8. A colliery decking plant comprising a movable empty-tub cage, a connter operated by tubs leaving said cage and adapted to lock after operation by a given number ot tnbs and thereafter prevent the passage et tubs until released, and means for controlling the movement of said cage by said counter.

7 9. A colliery decking plant comprising a movable empty-tub cage, a counter operated by tubs leaving said cage and adapted to lock after operation by a given number of tubs and thereafter prevent the passage of tubs until released, and means for preventing movement of said cage unless said counter is locked.

8OQ A colliery decking plant comprising a movable empty-tub cage, and means set into operation by a tub leaving said cage for preventing movement of the cage until a given number of tubs have lett the cage.

8l. A colliery decking plant comprising movable empty-tub cage, a ram for shifting tubs in said cagerand means for preventing movement 01"' said cage unless said ram is clear of the cage.

82. A colliery decking plant comprising a movable emptytub cage, a ram for shifting tubs in said cage, and means for controlling the movement on said cage by the position of said ram.

In Witness Whereofl have hereunto set' mv hand.

l?. M. CASTLEMAN. 

